resmoke.py supports setting --mongod and --mongos command line options to have MongoRunner use those binaries when spawning mongod and mongos binaries, respectively. This behavior interferes with multiversion testing (i.e. binVersion != "latest") because the path to the mongod-* executables are resolved relative to the MongoRunner.mongodPath path even though they are meant to be findable on the PATH.
The work on this ticket would involve not using MongoRunner.mongodPath or MongoRunner.mongosPath when binVersion != "latest", and to instead use "mongod" and "mongos" as the binaryName.
Additionally, the appendSetParameterArgs() function should modified to treat "path/to/mongod" and "mongod" as the latest version. The baseProgramName needs to actually get the basename of the programName variable.