I realise I'm coming a little late to the party here, but you could try picking up a Yamaha RGX Drop6 secondhand. They weren't expensive to start with, and should be reasonably cheap. They're 6 strings with a 26.4"ish scale, tuned to B, E, A, D, F#, B. String tension is about the same as a normal guitar, provided you use the right string gauges (bottom end is something like a 0.62 if i remember right). I've had one for a good few years - gives a 7-string sound without the need to learn new fingering, which is great if you're lazy (like me).