Help identify mid-90s steel MTB frame If anyone knows what this frame is and could help me identify it, I would be most grateful. 

Distinctive (or not) details of the frame:


Seat tube top: is concave, curved in.
Rear brake cable routing: brazed-on noodle on the seat tube.
Seat post binder bolt: is behind the seat tube.
Top mounted cable routing: the shifter cables and the rear brake cable are routed along the top of the top tube.
Head tube: the reinforcement rings.
Rear derailleur cable braze guides: are under the seat stay.
Ritchey rear dropouts: incl. flat (vs round) seat stay and chain stay ends  &amp; eyelets.


Measurements:


Weight (approx.): 1.886 kg
Steerer: 1 1/8 inch
Seatpost (approx.): 26.6 mm
BB (British): 68 mm
Dropout spacing: 135 mm
Top Tube (approx.): 590 mm (c-c); 615 mm (effective); 28.6 mm (diameter out)
Seat Tube (approx.): 435 mm (c-t); 390 mm (c-c); 28.6 mm (diameter out)
Head Tube (approx.): 110 mm; 36.5 mm (diameter out)
Down Tube (approx.): 32 mm (diameter out)
Chainstay (approx.): 420 mm
Reach (approx.): 460 mm


Serial Number: B99XXXX (B plus 6 digits)

Other (Ir)Relevancies:


Came equipped with a threaded 1 1/8 inch triple butted (TB) rigid
Kona Project 2 (P2) fork.
Originally from Germany.
Preliminary discussion: http://www.retrobike.co.uk/forum/viewtopic.php?f=1&amp;t=377616


Close matches so far:


Many Scott mid-90s models.
Biria MX 700, but round seat stay and chain stay ends and 27.2 mm seatpost.


All input appreciated, any ideas or suggestions are most welcome.

Thanks
I owned a Ritchey steel frame from ~1999 and this doesn't look like a Ritchey of that era to me.  


The cable stops are welded to the top of the frame.  Mine were welded underneath.
There are no lugs on the frame.  All the Ritcheys I have seen from that time had lugged frames. 


My guess is that the frame was built by someone else using Ritchey dropouts.  I would think those unusual looking cable stop clusters might be a clue, but maybe they're more common than I am guessing.

There's more info here that seems to indicate (though not definitively) that the serial number doesn't match the pattern of that time for Ritchey, and that the company was in fact selling parts to other manufacturers.