I have actually already posted this in another thread somewhere but for t-shirts you can take baby onesies and cut them a little to make some cute personalized shirts. Add some paint, rhinestones, ribbon, etc and you'll have a really cute shirt. I made Reagan a couple you can check them out at her dogster page the bottom two pics....
www.dogster.com/?132573
On the audrey hepburn one I should've made the picture smaller and cut the shirt shorter. You really could get away without any sewing.