I had trouble with setting wscons to 50 line mode.  In case anyone else   
has tried and gotten frustrated like me, I hope this helps:

For wscons:

in your kernel config:
options 	WSDISPLAY_DEFAULTSCREENS=2	# at the least 1
options 	WSCONS_SUPPORT_PCVTFONTS	# support PCVT fonts

in your /etc/wscons.conf
font	pcvt	-	8	pcvt	/usr/share/pcvt/fonts/vt220h.808
font	ibm	-	8	ibm	/usr/share/pcvt/fonts/vt220l.808

#screen	0	-	vt100
#screen	1	-	vt100
screen	3	80x50bf	vt100
screen	4	80x50bf	vt100

be SURE to put the pcvt font first.  If the ibm font is loaded first, you   
just get
the top of the font and when booting, the wscons setup will complain
about not being able to find proper font and give you 50 lines of half
characters.(I'm not sure why the order is important?  The man doesn't   
mention this.)

Use 80x50bf not 80x50 otherwise you get 50 lines of half characters.  I   
do not know what step are needed to get just 80x50 to work.

You will notice that screen 1 & 2 are remarked out, these are the two   
screens defined in the kernel with WSDISPLAY_DEFAULTSCREENS=2.  If you   
unremark them, wscons will just complain that "device busy" for those two   
virtual terminals and do nothing to them.

e.g. 'screen 1 80x50bf vt100' in wscons.conf will remain 25 lines because   
of it pre-definition in the kernel config file.

This is really important, in /etc/rc.conf:
wscons=YES

Hope this helps someone.

It wouldn't be a bad thing to have information on 50 line mode in the   
i386 how to on the web site.

For ye olde pcvt:

132 col:
printf "\033[?3h"
stty rows 25 cols 132

80 col:
printf "\033[?3l"
stty rows 25 cols 80

50 lines:
scon -s 50

Now after all of that, it seems that pcvt doesn't support much of   
anything anymore, at least as of 1.4.x. (I'm up for a correction on this)   
 I tried getting pcvt to set the console to 50 line, nothing happened.   
 The man says pcvt can support 28, 40, 48, and 50 lines mode on VGA   
cards, but 80x25 looks like all it can do anymore.

If you run the VT animation demos in
/usr/src/arch/i386/isa/pcvt/Utils/demo with playvt (compiled in the same   
dir with make) scons is a bit faster and smoother than pcvt.

jam

BTW: If you're now curious about the vt demos, playvt's syntax is:
./playvt -d <delay> -f <filename>
On my Celeron 300 I had to use a delay of 30000.