Here are my thoughts:
First, there are advantages to the Buyer doing the inspection promptly. The main one being that If there are issues with the property the price can be adjusted PRIOR to the short sale being submitted to the lender. Secondly, why would a Buyer want to wait several months to do an inspection only to find out the property won't work for them?
As a Short Sale Listing Agent, having the inspection done asap is not the real issue. The real issue is the inspection contingency. If it's a good Buyer and they truly just do not want to spend money on the inspection before the approval then just write the contract and remove the inspection contingency. This way the Buyer can do the inspection later but if they cancel over it they lose their deposit. Make sure you get a good deposit at time of contract.
If the Buyer is still not agreeable you could negotiate the contract allowing the Seller to continue to market the property and accept a better offer if one comes in. Give the buyer a First Right of Refusal.
Basically you need to make sure the Buyer understands that the Seller needs them to commit to the deal. If the Buyer won't commit then certainly the Seller shouldn't.
There is nothing worse than a Buyer using the inspection contingent to get out of a deal after we have worked for months to receive the Short Sale approval.
What say you?