Is there actually a seven string set which consists of 10-52s with a low 60 or is that just wishful thinking and in reality you'd have to mix sets up?

http://www.thomann.de/gb/dean_markley_2504c_lthb.htm

Dean Markley 7-string, with 0.60 as lowest string.
This place probably has the cheapest price for those strings.

Good luck.

Thanks Archetype!

This is much appreciated