Okay - I'll eat some crow on this one. I didn't know such an adapter existed. Yes, that could be very handy in reusing the fork you've ordered. It seems more likely to me, however, that you'll buy a complete frameset or bike next and won't end up reusing this 1" fork. (In which case you could ebay it I suppose.)

My opinion still remains that you are sinking a lot of money into this project that would be better off in a 'better bike' piggy bank. But, it's your money and there are ways to make it work (for the most part). Research the wheel options very closely and best of luck to you.