These were posted on another forum, but I thought some of the readers here might be interested. These are reasonably priced DROs that can be fit to your machine tools. Not a completely new idea (using a digital caliper is the same thing), but the readout/display is seperate so that is kinda nice.
6"
http://www.amazon.com/dp/B003JU46J4/...3080_pe_vfe_t3
12"
http://www.amazon.com/dp/B003JUII2A/...3080_pe_vfe_t2
24"
http://www.amazon.com/dp/B003JULE4Y/...3080_pe_vfe_t1
35"
http://www.amazon.com/dp/B003JURUJM/...3080_pe_vfe_t4