I myself provides this kinda service but I don't call it 'spree'. I would rather label my service as ur 'personal shopper' as I will buy immediately upon payment confirmation to save time

I normally WILL NOT charge my buyer extra if they want the items to be delivered straight to their home, instead I charge them lower (I don't have to do local postage and lesser hassle). I would normally deal with the seller, to have it delivered to the REAL buyer as I'm only paying on behalf of the buyer (though some sellers have the policy of not delivering it to an address which are different from your account i.e paypal or credit card). If the seller refuse to deliver it straight to the buyer, I would then charge for the local postage.
As for you TRACKING CODE, so far I have not encountered any issues as if my BUYER opt to have the tracking code, they will get it from the SELLER. Like you said, pay extra for the tracking code and faster international delivery (not to me, to the seller).
I don't know bout you, but the only reason I can think of getting the items delivered to seller first is because he wanna make sure the client don't cheat him even when they receive the items. As for me, it's all about trust and I gained a few loyal customers from this trust

TS, where did u buy from the seller? Through eBay or other sites?