"Some experiment" sounds interesting
. But I don't suppose it makes sense as a "Feature" of Reaper's.
AFAIK, the project sample rate setting is mainly used to convert files on the run, to set A/D D/A interfaces to work at the appropriate rate and to provide it to plugins to have them calculate their "virtual real" timing from sample numbers.
In the GUI you supposedly could live with a factor 10 in mind.
-Michael