I started a new topic on this here
http://forum.ppcgeeks.com/showthread.php?t=25903
seeing if any of you who've tried ghetto's rom having this problem as well. I reflashed back to jd's test rom and now I"m able to get incoming calls while I'm on tomtom, garmin, google maps when they are using gps.
It doesn't seem I was able to get incoming calls while using those programs on ghetto's rom.