Originally Posted by dddd

What model of SRAM rear derailer?
ESP (i.e. 1:1) series derailers will not work with any Shimano or "clone" shifter.

Not all 7s SRAM rear derailers are Shimano-compatible, some are.

But, you could get a good, used Shimano rear derailer for very little money, to work with most road shifters of the same number of speeds.
Does Dallas have a convenient bike co-op where you can buy parts for next to nothing?
Visually check any used derailer that you consider buying (look for the flat end of the mounting bolt to be parallel with the "cage" that holds the two pulleys). Don't buy a bent derailer!

I wouldn't kluge together 7s and 8s Shifters, derailers and freewheels. It adversely affects shifting performance, and most definitely affects how long of a service interval that the adjustments will last. In some cases (using STI shifters), a setup with a "locked-out" 8th gear position results in an inadvertant over-tensioning of the cable, with the shifter then stuck (mechanically locked-up) in the "beyond-lowest" gear position until cable tension can be manually relieved. Not good for the cable, or for the shifter!

"Finicky" 7s shifters/derailers are a big part of why SunTour went out of business, and you don't want anything to do with that. Stick with compatible components!

Originally Posted by Classtime

Just maybe your new tourer would be perfectly happy with bars that fit the shifters? I know they are not drop bars, but Soma Oxfords get me pretty aero with multiple hand positions and fit MTB levers and shifters.