Datacolor, better known for their color management tools, have introduced a focus calibration device for DSLRs. It was introduced at Photokina last September, but flew under my radar till the PR company here in the UK contacted me recently to send a sample. I'll reserve judgement until I've fully tested it, but it looks well-made and robust. The SpyderLensCal lists at $59, 49.00 Euros or £41 plus VAT. That's a considerable saving over the $179 rival LensAlign PRO.
Datacolor has also released an informative video.