Right then, I am thinking of putting a rigid fork on my hardtail and sticking a 29" wheel on the front, the frame is corrected for 100mm forks so could I use a standard 26" rigid fork (like the On-One 440mm axle to crown) just in case I don't like it? Anyone done it?

Yep. Did it with a 100mm travel hardtail using a set of superstar carbon forks. Was fun for a bit, but I found it a bit pointless to be honest. Have a go though, you might love it 🙂

tidy, if i hate it i'll go back to 26"
Its going to be a sort of commuter/race hardtail, its sub 24lb with Vanillas on it and i've not tried to loose weight on it yet

I did it with my 45SS last year, fun but pointless. Haven't changed it back to 26" though yet (won't anytime soon).
456SS frame, 26" On-One carbon foks, 29er Bonty wheel.

I thought this would be an ideal winter project with an alfine but then I it never happened

commuter/race hardtail

Now there's a niche you don't often see! 😉

aye its running a 34 front 11-32 rear with semi slicks on it, its pretty quick on the road but i've not tried it out offroad yet (will do next week I hope)

Tried my Love/Hate as a 69'er with 440mm fork (On-One as it happens) and it made the front end too slack. The geometry is much better kept as per originally designed head angle and with 29" wheels both ends it rides really nicely with road/cross tyres.