Hi,
I have aleardy built software like this. What you are asking for is like bet365, pinnacle, bwin etc. TIt also has a portion that is geared to p2p betting like that at betfair.
What I am offering is complete opensource code I built before, I can direct you to a demo. There may be edits that need to be made and the price is negotiable, I will not be involved in the development, however there is also a complete booklet of the system and API that I built with complete open source code. Questions I can answer, however I am unable to code anymore, I need the money but no longer have the time to code.
If you are interested let me know.
Thanks,
Carl