I recently bought a used frame that I learned - only after receiving it - is "custom" in that the head tube is shorter than standard. It appears that a portion of the bottom of the head tube was cut off, so that the head tube sits lower on the fork crown. As a result, the entire frame is tilted forwards - the top tube slopes downward and, most importantly, the head- and seat-tube angles are steeper. As it is, the frame is unrideable by me. Setting aside returning the frame (an option I'm looking into), is there a way to problem-solve this? Specifically, is it possible to put a spacer of some sort at the bottom of the head tube? I imagine it would have to go somehow between the head tube and the lower headset cup, or between the crown race and the fork crown. I'm looking for a solution short of having a framebuilder actually weld an extension onto the headtube (it's titanium, and I don't want to spend that much money fixing a frame that was wrongly advertised. I'm just looking to see whether there is a simple and cheap way to solve the problem that would avoid the hassle of making a complaint with paypal.)
Thanks for any suggestions.