One thing that is even less available these days than six-shootas and kannons is bionikz. Whilst Orks are easily available, if you need to fit them with a shoota arm you’re out of luck, unless you’re willing to convert the part from scratch.
I don’t think the shooty arms are available just yet but I don’t imagine it’ll be too long until they too are available in the Maxmini store.
I also hear that there are further bits to come, which makes me happy.
They’re priced at €5.65 for a bag of five randomly selected arms, or $8.36 (US). Not too shabby!