Tea Tree Embroideries has some really nice roses on Embroidery Passbook. If the colours don't suit, they can always be changed.Both sets are on special for half price.
The bottom picture is a the stitch out of one of the designs.
there is one in or at you embroidery .com free by our very own cutie go look hugs
DBS has some lovely roses. $2.00 per set.
Embroidery Library has many sets and individual designs available.
consider the idea of Applique embroidery. It makes roses look nice.
Ms. Veronika has some on Amazing Embroidery Designs. I am not sure how well they would stitch out on the fabric you are using. I would suggest using a cut-away as a backing. I think she has done a great job on all of them and I usually do not like the roses digitized by other sites.