Hi,
SReevesTX, the letter you're describing sounds like the sign for "r," so having the students do that and making an arc to the side of the body would be "restroom" in sign language.
I was having my students use two fingers to signify bathroom, but I like the idea of using sign language. I never thought to use it that way before. This year I'll have them sign for bathroom, making a "t" and shaking it back and forth a few times.
A great resource, if you're interested, might be the American Sign Language browser
http://deafness.about.com/gi/dynamic/offsite.htm?zi=1/XJ&sdn=deafness&cdn=health&tm=26&f=20&su=p284.9.336.ip_p736.8.336.ip_&tt=2&bt=1&bts=1&zu=http%3A//commtechlab.msu.edu/sites/aslweb/ I'm definitely going to look to it as I need gestures for things. You can see video of the sign being shown rather than just a picture.
Thanks for sharing the great idea, believerjen!