An 8x10 enlarger?  What are you putting in the 8x10 enlarger?  I gather
then that you go out with an 8x10 view camera and have a 16x20 linotronic
negative made from the 8x10 negative -- which might (or might not) pay off
for platinum (if that kind of sharp/fine is your esthetic)  but not
necessarily in other "alt" media. I myself begin with a 35 mm negative, as
for the most part do my students, at least at this point in their careers.
In fact I cannot imagine making the photographs that *interest me* with
any other format. (I don't mean I'm not interested in *looking at*
photographs originating in large format, just not in making them.) 
> ... *my* situation, is this:  I don't have a darkroom.  For this 
> reason my current, practical, options are to have 16x20 analog negs made 
> by a custom photo lab, or have a service bureau make 16x20 digital negs 
> for me.  Give these two, and only these two, choices, it is less 
> expensive for *me* to have digital negs made. 
Gosh David, if you can live without a darkroom, what more can I say?
Well, just that some of us would have to rent more space to add one more
piece of *digital* equipment!  I mean, mine has gobbled up what used to be
a dining area, and though I think sometimes it would be nice to have a
scanner, et al., don't know where I'd put it!
PS. My 4x5 Omega D2V cost $300 used. So it had a few dents -- not a big
deal.
PPS. This discussion -- with Darryl's input above added -- may have well
limned parameters of the moment. Or at any rate I trust we added light (at
least it was added for me) with no more than a comfortable amount of heat
.. hurray! 
Cheers,
Judy