No problem with trying to go it on our own - to me, that is what independence is all about.
Regards contracts. If in the EU, then (while I know there are some special rules on defence matters) there is a question of EU competition.
If not in the EU (ie if Scotland not allowed back in, or UKIP brings the UK/rUK out) then maybe there are EFTA or EEA rules? I don't know.
At the end of the day, any government should be seeking value for money. Hopefully Scotland will continue to provide that.