Appgen has just quietly released a Linux version of their MyBooks package which has a free trial of 30 days. The price is $99 US. I have it and can say that it is the first Linux accounting program that I have found to be suitable for BUSINESS. It seems to be a version of their flagship product Power Windows or somesuch with a Java interface. However, you can dispense with that interface and get into the real nitty gritty stuff directly.
So far the only caveat that I can find is that it is totally geared towards the US market. Other than that, I am overjoyed. Brian