[NTG-context] memoir-style chapter heading

[jbf]

Am completely new to using Metafun, which I presume I would need to use 
to achieve a Hansen Memoir-style Chapter heading (chapter title 
overlayed on a large lightgray number). Of course, I am assuming I would 
need to use Metafun to create this...

So my first question is to ask if I could achieve the same effect 
without Metafun?

I have read through the Metafun manual, and I think I can understand how 
to overlay text on a graphic (MP), but it would be currently beyond me 
to draw numbers of the kind we find in, say, the Memoir examples.

Has anyone created such an example? I was keenly looking for one in the 
manual and elsewhere, in terms of ConTeXt/Metafun commands, but could 
not find one. But I'd be quite prepared to 'have a go' at this, if I had 
some pointers of just where to start! I assume I would have to 
\defineoverlay[number] and then add text on top \framed (but without the 
frame borders). Am I at least correct about this?

Julian