One thing that's occured to me is that, if you wanted a really durable space station, you could send up a Bigelow module with a big 'cargo' docking hatch on one end, then send up a 'tin can' cargo module containing rigid panels. You dock the cargo module to the inflatable one, then, in a pressurised, shirt-sleeve environment (i.e. MUCH safer than a spacewalk), you use the panels to build a rigid, pressure-tight hull inside the inflatable one. Cover those panels with built-in attachement points and you're free to use the space any way you want to, instead of only having rigid stuff attached to the core. Also, you've now got the cargo module, which can have things like solar panels and experiments attached to the outside of it.