Thunderbolt Display Refresh?

Hey all,

I am currently trying to suppress my itch on buying a new monitor. I purchased a 15" rmbp fully loaded and I have been extremely impressed. I sold my desktop off because it sat idle now due to my new rmbp, but there is one thing I haven't fully worked out, a desktop setup. I have a Dell 2713HM which I believe has the same panel as the current thunderbolt display. I am in dire need of docking solution, but the only ones that really fit my needs(dvi 1400p @60hz) are around 200 dollars.

Looking at the thunderbolt display, it looks like it would be a perfect for my needs, but I really want to hold out until apple potentially upgrades to a 4k display. I'd imagine that it would be around the same price as the current monitor and my Dell still goes for 500 used on ebay. With all that in mind, i'd be stupid to buy a 200 dollar docking station when I could sell my monitor and get the thunderbolt display for a little more.If anyone thinks otherwise, ie buying a docking station is the way to go, share your experiences.

When do you think a refresh would be in order for the thunderbolt display?

Thanks in advance,