[NTG-context] Specifying maximum width of a frame

[Aditya Mahajan]

Hi,

  I want to specify the maximum width of a frame. If the size of the 
box is smaller than the maximum width, I want a tight box. Something 
like

\frame[maxwidth=5cm,align=middle]{Small} should give

+-----+
|small|
+-----+

while \frame[maxwidth=5cm,align=middle]{A very very long line that is 
split at 5cm} should give

+----------------------+
|   A very very long   |
|  line that is split  |
|      at 5cm          |
+----------------------+

Is there something builtin that does this, or do I need to play with 
scratchbox cum suis.

Aditya