You're not alone. I've got the big house, big garage (big mortgage), three kids with the oldest being one year from college($$). The wife took last year off and cut our income significantly, but is now back at work as a Unix Admin so, our income was back to normal for a month or two. However, I just walked away from a very nice, regular income as a systems development manager to become a partner in a very small consulting firm with no guaranteed level of income.
In the middle of all this is my Z project. I've got the rolling chassis back on the ground, but the engine is still on the stand and the T56 is collecting dust on the floor. The Velo Rossa body kit is stored on the RV pad next to the house. I started the project several years ago and it seems I'll never get it done. Spare cash for the car is scarse these days. Most of the project money dried up a long time ago, but I try to squirrel away a little money here and there like Tim talked about. Every now and then I blow the dust off the car and make a little headway.
I've entertained the thought of selling the whole project several times, but I can't seem to go through with it. Hang in there, be patient. Heck, it took Pete Paraska 10(?) years to complete his work of art.