Looking at the pricewatch of tweakers.net, this indeed shows an upgoing trend for the PRS-T1:
I guess this might have something to do that shops that are really 'into e-readers' have discontinued the PRS-T1 (look at bol.com in the Netherlands), and that the only available shops that still carry this devices have maintained their already high price.
Look at Salland.eu, they only have a few ereaders, and only the Sony and Pocketbook are of better known brands. I also saw the Sony at Otto.nl, who carries only this ereader.