Fred De Long had a lugless custom built frame made for him in the early 70s. It had unique fork ends with a slot that allowed him to move the front wheel about 3/4" (20mm) forward and back to test the effects of fork rake and trail.
There's pictures of the fork and results of his testing in his book "DeLong's Guide to Bicycles and Bicycling" (1974 & 1978). He discussed the effects of trail on things like handling on gravel roads, riding hands off and so on rather than just the racing oriented testing done by many others.
Chas. Colerich Oakland, CA USA
Ken Freeman wrote:
> I too have had some frame experiences that were initially upsetting, but
> which I now see as having been inevitable. Wanting to try low-trail
> geometry, I tried to find a frame expert who would add rake to an existing
> 531 fork. I spoke to two KOF builders. Both tried to talk me out of the
> job, explaining the technical difficulties and attendant risks. One refused
> the job outright, and the other would "do as the customer requested," but
> was clearly not on-board. I've decided to satisfy my curiosity another way.
>
> I really didn't want to look to other builders, and I didn't want to do a
> frame modification with a builder who did not think I was doing the right
> thing.
>
> I'm very glad they were honest.