Any alternate summoning rules that work?

[Surgo]

I've always been interested in playing a character that summons other things, but the summoning rules are pretty dissatisfying. The Summon Monster lists were written for the SRD monsters, and books will occasionally expand them, but there are a huge number of creatures that might fit on a list that just never get touched with such.

So, has anyone written any rules for summoning that try to make it more generic and inclusive (ie, summons based on CR or something)? If not...let's see what we can come up with.

[Mikka]

Summon monsters based on CR, compare to original monsters, talk with your DM about it / Thread.

[Surgo]

Summon monsters based on CR, compare to original monsters, talk with your DM about it / Thread.

"talk with your DM about it" can be said about just about anything. I'm looking for systems that are already here, not ones I have to invent myself.