And by cheap I don't mean a carbon frame for $500, I'm actually looking for an aluminum road frame, welds don't have to be ground, cro-mo fork is fine. It will never leave the trainer. Found some on ebay for $115, but the rear dropout spacing is 135, and I'm building around 10 speed so need 130mm spacing. Anyone know of a source?

If you looking for just a frame to build up a trainer specific bike, I would suggest craigslist. Lots of older aluminum bikes there. Just strip old and install newer 10 speed stuff.

AFAIK, the QR spacing is the same between 10 speed and 11 speed hubs. Or at least I've had no issues when I upgraded my 10 speed bike from 2011 to 11 speed in 2016.

135 mm is disc-specific or MTB .... road runs 130 for 8-11 speed---has for over 25 years.

And I am sure if you are willing to take the risk, you will eventually find a $100 or $150 frame on Ali-Express. You might even receive it.

I wouldn't ride it, but you might be fine.

https://www.probikekit.com/brands/kinesis.list

I had not thought about Ali-Express, thanks. I'm familiar with Alibaba, but for some reason thought they only sold in large quantities. When I say I won't put it on the road I'm serious, so I would even use a cracked CF frame if I could find one. True on the spacing. I found a cheap frame fork combo that was also available as a full bike (7 speed), but realized right before pulling the trigger that the rear spacing was 135. Guess anything designed for 8 speed and up with rim brakes should be fine though.

What is your actual budget? You should be able to find a decent aluminum frame and fork used on eBay for around $200 with some patience. You can probably find something for $100 off Craigslist depending on your local market. There were some $300 Chinese carbon frames on ebae recently

I would love to stay under $150, unless I find a good deal on a full bike that I could easily part out.