Designers just can't seem to get t-shirts right. I don't know why they don't hire artists to create them.
One of the down falls of being a t-shirt artist is that the selection of wholesale t-shirts is terrible. The cuts are usually off and the fabric is cheap and cardboard like. Back in my t-shirt designing days I did come across a company that did some light weight jersey (and the owner was nice) - Alternative Apparel - but I couldn't afford them. Designers have the cash flow to spend on beautiful jersey for t-shirts but they don't have the right artists working for them. I stumbled upon Red Bubble today. It's a community of artists who put their work up for sale online. There are some great t-shirt prints. Unfortunately, the t-shirts they're printing on are American Apparel and they have a terrible cut. The 'Classic Girl' fits too tight and the fabric makes you sweat and the 'Standard American' has a bad neckline and boxy sleeves. However, the shirts are so reasonably priced and the designs so original I'd take the chance and take my scissors to the neckline and sleeves of the men's Standard American.
There are lots of vibrant colors and designs to choose from. Being a fan of the basic black and white tee I chose these three off the top in a quick search.