a fun maemo arts and crafts time then....
great.
But if folks wanted something done as you said
"I would really like that and be honoured to be marked by such somehow, would it be a t-shirt, a badge on a backpack, what each one gets in his mind."

Then there is cost involved.
Time to do it is cost.
T-shirts cost
Badges cost
Printing / producing costs
and there will always be ones that don't come out properly ..in the process...that loss costs.

So whether it is individually done or professionally done.
Your suggestion costs.
It is always much much more expensive to produce one ..or a couple ...of a thing..
And always is cheaper to produce en masse ...

I have done quite a few such projects here in my spare time.
I didn't mind the cost then to produce the protos
It was fun and I wished to have at least for myself the aimed items..
whether it was t-shirts, patches, badges, replacement n900 body in a more durable and aesthetic casing..
Whatever..

I still make such ...but only for myself..

Since for the community it is not viable ...it is just a cost loss.