And how am I going to find it if you dont opensource it? Seriously, this is a disaster waiting to happen, and assuming you are legit, you do not want to have sold unvetted software to an exchange. What makes you think you will not be held liable if (or rather when) it gets hacked?
The only way I *might* see this work is if you opensource it with a commercial licence. Let anyone check your code, but dont allow its usage for for profit enterprises without paid license. Not that that will guarantee a lot, it would take at the very least a significant bug finding bounty that has run for quite some time before Id even consider using an exchange running your code,.
For the record, there are plenty of similar opensource projects:
https://bitcointalksearch.org/topic/info-open-source-trading-platforms-87836
Yeah you can always use them After that you will be in "list of hacked" exchanges like mtgox and the other ones I can guarantee that this source is very high secured. If you have interest please contact me and i will send you a DEMO site to try your hacking skills