The niche is good. But the second words are not very used in combination with "pet". There are no searches for any of these two word combinations... I think the best one might be petgarment.com. I would say low to mid $xx.
"garment" too plain cloths sounding. Still logical and I can see it working for cold weather people concerned about smooth hair breeds. But I would think the money in costumes. The person that owns petapparel.com has it on godaddy for 21k
I like the idea about developing it, it's a quality start. Good Luck