I think that's the thing, 20" and 26" trials is established in both street and competition trials whereas 24" isn't; I know this is primarily due to the lack of availability but as there has been no clear adoption/inclusion of the wheel size for UCI or BIU rules it's a chunk of your potential market gone simply for that reason. It's a big jump to make for a company and I don't think that the jump will be made until the competition rules side of things is clarified. I've got to agree with Mark too, the majority of street riders don't tend to splash out big money on new frames, from what Joe has told me I would gather that the majority of their frame sales comes from the competition side of the market.
The other issue i'm finding is that there isn't a massive availability of decent parts for the 24" TGS scene. I have £50 Schwalbe tyre waiting for the Echo TR rear rims to come back in stock so I can at least build up a decent wheel to compliment the light frame.
Brand New In Box Mark.
I would say both innovative and new.