You could get some G-Sport wheels
Failing that, how about widening your horizons? You have three solid bikes, look into other things, off the top of my head:-
1. Plan ramps, dirt-jumps, little alterations to natural terrain like drainage ditches.
2. Plan a trip.
3. Get a motorbike. (I have been amazed how the experience of riding a motorbike has made me think about how I ride BMX and MTB more).
4. Do a wild paint job on one of your existing bikes.
5. Write a long and detailed rebuttal of why all my ideas suck and try to work in as many references to cheese as possible.
6. Send time wasting letters/emails to companies and see if you get an answer. For example:-
Dear water company,
I have been relatively happy with your service over the last few years, but some weeks ago I noticed that my warm water taps no longer work. The cold taps all still work very well, but all the water being supplied to the warm taps appears to be absolutely stone cold. When I tried to phone your help line about this issue I received a a tirade of abuse... etc etc.
G.
Funny you should say all this, because this is exactly what has been rolling around in my head. BUT:
I've got a set of G-Sport wheels on one bike (marmy/ratchet to roll and ribcage), and my other set of wheels is antigrams laced to birdcages.
1. Very time consuming (I have 4 children)
2. This is a good idea. I'm going to put some time and energy into this.
3. God I miss my dirtbike. I haven't picked one up since because of time, money, and my 4 kids.
4. I'll never be happy with the results.
5. Dang, I should have been writing about cheese. There is a delicious local cheesemaker that produces a cheese called 'Barely Buzzed.' It's a semi-hard cheese with a coffee rind.
6. Aint nobody got time fo that.
I'm really surprised that you didn't suggest picking up a different discipline such as MTB or road, but that crap is expensive. Maybe I should look into a Fairdale...