I have been interested in the E680i for a long time, but the lack of GSM 850 (rare for Motorola) meant I could not get it, which is a shame since I think it would fit my needs well. Anyway, I would say that you definitely should have GSM 850 on your touch screen, which eliminates the Sony Ericsson and Motorola E680i. Really, the A1200 is your best bet or you could just give in and go for a Treo.
Its really difficult to get a smaller phone with a touchscreen. Because of the nature of the design most people would want a touch screen to be as large as possible, making the design larger.