Thanks for the input.
For various reasons, including shipping costs, import duties, import hassles, time and my budget, importing a touring bike isn't an option I will consider. I also don't think a touring bike will buy me a lot over my trike, other than being able to deal with roads where single track vehicles can negotiate, where a trike can't.
As for comfort and the ability to handle a good load, the touring bike option is way behind the trike I just sold (IMHO).

I've been riding the trike quite a bit here, and have a good idea of the relative abilities.

The Cruzbike conversion is one I've considered, and have not ruled out. My issues are that some of the roads I travel already have me spinning the rear wheel on my trike (even paved and with a bit of a load to weight it, and that's in my subdivision), and then the fairly chaotic traffic here, where slow speed stability and responsiveness is key.
Lastly, there is the issue of finding a suitable donor in my size: I'd like to ride it as an MTB first, to see how I get on with the concept before investing in a Cruz conversion, and so far I have not been able to find any bike in my size other than a 29er.
Or will a Cruz be OK using a 29er as a base (I'm 6'2)?

I've also considered RecycledRecumbents. I've had a LWB bent before of very similar dimensions, and as a result would really like at least rear suspension.
Again, finding affordable donor frames of suitable quality is an issue.

Last night I found a potential supplier of carbon fiber and composites in the USA, who seems able to meet my needs as far as payment and shipping terms go, I just have to work the financial and duty / tax issues out, as well as getting a complete plan and list of materials. So I could still build something: my ideal bike for the way I ride here is likely the Azub Max and 6, and the HP Velotechnik Grasshopper, so something with similar geometry and components would likely work.

But the reason I like the 29er idea is there is almost zero waiting time, and known upfront costs. I have a trailer, I can likely get luggage made locally (if I can find suitable material, I've been looking without success so far in my city).
As for the chainstay issue, my understanding is that the 29ers have longer chainstays than 26" MTBs, maybe I should go and measure one up to make sure.