Finally viable after so long, or...?

[Vrock_Summoner]

Can non-full-casters who take Improved Spell Capacity enough times eventually qualify for Epic Spellcasting, despite not naturally getting 9th-level spells?

[Telonius]

Looks like it. If you're (for example) a Paladin 21, and you take Improved Spell Capacity once, you can gain a 5th-level slot. At Paladin24, you could take it again to get a 6th-level slot; a 7th at 27; an 8th at Paladin30, and a 9th at (Paladin30/Whatever3). At (Paladin30/Whatever6), assuming you met the skill prerequisites, you'd qualify for Epic Spellcasting.

(EDIT: Note that some of the half-casters - like Paladin and Ranger - do not get Spellcraft as a class skill. You'd need to be level 45 before you qualify, if you don't get it as a class skill somewhere else).