I emailed the woman who wanted to do the trade and said 'no thank you.' I know that the LV is probably a smarter bag to own, as it will never go out of style, is immune to most damage, etc..., but the papillon style isn't practical for me. If it was a speedy, however, I would have done it in a heartbeat. I got a fabulous price on the Sophia at Bloomie's when I originally bought it, so even if I could only get a few hundred bucks back for it, i'd be totally fine with it. The next bag on my list is a Julianne, and I'd love to make some $ to put toward one.
You did the right thing by not trading since Papillon isn't practical for you.
Most Sophias gets $200-$300 on ebay, I'm pretty sure that Speedy goes for more than that. Honestly, you need more than 1 Sophia to trade for a Speedy (very good resale value).
There are bags that we enjoy looking at on others, but we just don't love carrying them ourselves. Not every bag suits everyone's lifestyle/need, what matters is you love carrying it. Since you don't love carrying it, you should let it go and use the $$ to fund your dream bag like Julianne. =)
Good luck. =)