There are lots of companies that manufacture these items as promotional gifts, so it shouldn't be too difficult to track one down in the Yellow Pages. Try under 'Promotional Items and Incentives' and ask whether they do promotional clothing.
The shirt design is fine, any decent search on the web will find you a shirt designer; any good printer should then be able to apply sponsors to the shirts, finally the label is more difficult, to my knowledge custom labels aren't a standard addition, though if you were extermely specific with the designers im sure theyd find a way.
Designer: http://www.routeone-design.com/3D/designer.asp