You could build a box that holds standard frames. This is what we have done. Long hives are just Langstroth hives that have been stretched to hold more than 10 frames. Ours hold 33 frames in their 4 ft length. So we have the best of both worlds.... frames and no heavy lifting.
would you please give me a little more info
1) what depth is your hive?
2) do your frames have the standard lang topbar or are they like a TBH topbar?