Homebrew:Need Advice Regarding Constructs/Polymorph/Airships

[survient]

So this gets a little crazy, please bear with me:

I'm in a 3.5e group with a DM running his own campaign.

I'm running a Warforged Artificer with the leadership and craft construct, currently at lvl 13.

Since standard 3.5 gives you limited options for crafting constructs he allowed me to build my own using rules from http://www.kismetrose.com/dnd/CustomConstructs1.html with a Flesh Golem as the base template. Using the leadership feat he's allowed me to make it my cohort and let it gain character levels since I've given it a higher intelligence(similiar situation to a nimblewright). In exchange it has lost it's immunity to mind affecting spells.

We just finished off an adult shadow dragon and he now he wants us to head to "the clouds"; he hasn't given much more detail than that.

Basing a lot of my ideas from Eberron I immediately thought of an Airship. An issue I'm having though is that our party's spent a good chunk of gold towards building a second custom construct used for transportation. Essentially it will be a gargantuan sized spider construct with a hollow interior acting as the cabin. I'm wanting to add elements of the airship to the spiderwalker to enable it to fly; my DM likes the idea but needs me to flesh out the logistics and that's where I'm having some trouble. Airships use soarwood to float but leaving this spider with that material will make it fairly vulnerable. None of these constructs I've made immune to magic so ideally I'd like to do some kind of polymorph but most are only temporary in duration. There's Polymorph Any Object but that can't make rare materials. Currently the wood we have in abundance is darkwood so converting to soarwood should be about the same value; I'm just not sure if this would be justifiable. Another spell is Polymorph Other from Tome and Blood but that is 3.0 and I'd rather keep it to 3.5 if possible.

Am I missing a possibility here? All I'm looking to do is change the material of the construct; I'd like to be able to convert to metals but if there's a way limited to changing wood types I'm definitely interested. Any help would be appreciated, thanks.

[GenericMook]

I'd get a Fire Elemental or an Air Elemental bound to the constructs core, and technobabble your way to having the Elementals power the ship.

A ship running on a Fire Elemental would have to function on some basic steam tech., but you get the benefits of heated cabins and whatnot. And maybe even a superweapon, if you can get creative.

[survient]

We have a whisper gnome in our party and since we just came from the underdark have a lot of "shadow" related abilities. Our DM is allowing us to use a "Shadow" Elemental from Tome of Magic: Pact, Shadow, and Truename Magic as long as we let him set up an encounter to capture it. For now we've been traveling by day but due to the nature of the shadow elemental we've decided to start traveling by night, at least while flying. The main advantage of soarwood is we wouldn't have to keep the elemental out 24/7. If the elemental was the only means of lift, normally you'd need somebody at the helm that whole time to keep the ship aloft. As a warforged I could do this as long as I chose not to renew my infusions but I'd rather use soarwood at least for the flying part.

I'm debating making the construct modular. The core would be made of X material that never changes, but it'd have components I could add/remove. Once I remove a section, it would be treated as an item/raw material as long as it wasn't part of the golem during construction, thus it would be eligible for Fabricate, which is exactly what I want to do. I'd just rather not have to add this tedious layer as a workaround if possible.

[only1doug]

My first idea on reading this was a balloon, Ballooning spiders really exist so why not go with that?

My application of the concept would be to create a combination of Liftwood and Silk that the construct could use when converting to airship mode, then you just need something to apply directional control (your shadow elemental somehow perhaps).

[Zanthy1]

What about a few permanent overland flights spells?

This would require a little communication with your DM, but cast that like 8 times (for each leg, maybe even 2 more times for the torso) and link it to the steering mechanism inside. So you are not always flying, but totally can if you want. This is of course mostly DMs discretion, and he may not allow it.

In that case, why not just build an airship normally? The technology is out there, why make it a construct when you could just make the real deal? Make it big enough to carry this spiderwalker.

This way you can fly in a dirigible and land and use the spiderwalker, like real military transport aircrafts. Want to make it even cooler? put a bunch of feather fall spells on the spiderwalker, and have it just jump out of the aircraft, to land in a hot zone. Very commando