I thought that Lane Bryant has some petites? I could be wrong though. Maybe that's just in some of their pants, which doesn't solve your tops and tees for summer problem.
I know I've seen plus size petites in Dillards.
Ok, I know these are hard to find...so I just checked Talbot's Woman ..and yes, they have Plus Petites. Here's a link to their Plus Petites tops/t-shirts page:
http://www1.talbots.com/talbotsonli...8&BID=&h=T&sk=T
Yeah, they're pricey - and you may not find a store in your local area, but I can vouch for the high quality of Talbot's clothing in general. It'd be worth it to order a couple of tops online, you'd get the good quality, and might find some nice tops for summer.
Also, while shopping recently in Dillards - I noticed that if you go for some of the more upscale brands - such as Jones New York, Jones New York Sport, Liz Claiborne and so on - their tops aren't all the super long style. Now granted, they will be pricey - for a t-shirt, but then I do think it might be worth it for comfortable summer wear.
Geeze I hate that. The super low pants, the overly long tops, and the overly short sleeves. These things don't do me any favours.
Try Dillards too - phone first though. Also check out some different brands/styles to see if you can't get away from the current 'overly long' tops trend.
Good luck - I know this can be a real pain. I hope you can find some nice tops.