Answers in the form of questions to ponder:
(I don't really need the answers, because the decision is all yours, but here are a few things to meditate upon.)
Is there any personal passion in you to do this? (Would you do it even if it didn't turn a profit?)
Can you proceed with no debt, or is that a prerequisite for this venture?
Can you bootstrap and avoid debt by selling before buying inventory?
Could online consignment selling support the start-up?
Would this fit into your artsy side, and allow you to expand the arts business?
How can you capture synergies between the two areas of interest?
First, I'd love to see your artwork if you can post any examples here.
Second, this is only my 2cents worth, but your new idea seems really risky to me. In theory, I like the idea of used equipment (not clothes though, not much profit in used clothes) but it's been my experience that folks tend to hold on to outdoor equipment. Not sure there's much turnover. Also, the margin on used things can be tough, especially with the availability of Craig's List, ebay, etc.
Also, in this economy, folks cut back on luxuries (including recreation) so at best, your market will be restricted. Not to mention that you'll have overhead concerns, especially with a retail space. If you stay online, you'll have the issue of visibility.
My suggestion would be to keep thinking, keep brainstorming, keep looking for a better risk with less debt. Good luck. (and I look forward to seeing your art).