This thread is titled "Pictures of your mining rigs!", not "talk about where you bought something"
Respectfully, where would your suggest we ask "Where can I buy that ?" if it's a result of posting a photo to this thread, if not here ? It's only natural.
I feel that personal messages are more appropriate for most of the questions asked in the thread, you've also got a better chance of getting a response unless it's someone who routinely visits.