Looking for a certain kind of video display tool

Try  NVIDIA
http://www.majorgeeks.com/download3294.html

How does a video driver answer this question?
Even if the ForceWare driver came with a diagnostic tool like I described, it's only good for NVIDIA cards.
I thought it would be fairly plain from the question, but the answer has to apply to any video card (and display).
Maybe I wasn't clear.
I'm not looking to put my Windows Desktop into an alternate mode, I'm looking to test various video modes to see if my card/display combo supports them.  What actually gets displayed, be it a test pattern or whatever doesn't really matter.

PowerStrip will let you run any custom resolution.  I am not certain if there is a "test" mode that will revert back after a set time has passed and you have not accepted it.   The download is free to try: http://entechtaiwan.net/util/ps.shtm

I tried it.
Doesn't help me.

As far as I know about using it, you use PowerStrip to set up custom resolutions.  These custom resolutions are available to Windows, which can be tried for 15 seconds.  What is it that isn't working for you?

The tool is way, way too complex for me.
The parameters boggle the mind.
During experimentation it did NOT come back from one test mode.
Bottom line: I do not like this piece of software, and it is not well suited for my simple task.
it's like hitting a nail with a sledgehammer - too much overkill.
Way back, I had the tool I needed; it displayed a test pattern in all known VESA video modes (text and graphics) and asked for a keypress between them.

Ok, I didn't know the degree of depth you were interested in.

How about DisplayMate: http://www.majorgeeks.com/download4189.html

I tried that one last week.
Unless I missed something, it doesn't do what I asked.
It displays various test patterns all right, but in the current resolution - it doesn't switch resolutions and color depths.

This is what the EDID of my monitor says:

(35)     ESTABLISHED TIMING I:
         720 X 400 @ 70Hz (IBM,VGA)
         640 X 480 @ 60Hz (IBM,VGA)
         640 X 480 @ 72Hz (VESA)
         640 X 480 @ 75Hz (VESA)
         800 X 600 @ 60Hz (VESA)

This is what the tool says when I try 720x400...

C:\Documents and Settings\Administrator\Desktop\setres>setres h720 v400
        SETRES v1.0 (c) Ian Sharpe December 2001. www.iansharpe.com
===============================================================================
A command line program to change the screen resolution, colour depth and
refresh frequency in Windows 98, Me, 2000 and XP. May/may not work with Win 95.

        SETRES hXXXX vXXXX [bXX] [fXX]

hXXXX = Horizontal size of screen in pixels          Not optional. 640 minimum
vXXXX = Vertical size of screen in pixels            Not optional. 480 minimum
  bXX = Bit (colour) depth such as 8, 16 24, 32      Optional
  fXX = Refresh frequncy in Hertz, e.g. 60, 75, 85   Optional.

EXAMPLES:
        SETRES h1024 v768
        SETRES h800 v600 b24
        SETRES h1280 v1024 b32 f75

WARNING: SETRES does not check the capabilities of your hardware. Windows
        is supposed to  reject unsupported settings but do not rely on this.
        If you specify unsupported settings, and in the event of hardware
        damage, I WILL NOT ACCEPT RESPONSIBILITY.

ERROR: Valid horizontal and/or vertical size not specified. 640x480 minimum.

Doesn't work...

It sounds like it has a minimum 480 vertical.  Any chance you remember what the tool you had sounded like?  I have gone over most of the ones I'm familiar with.

I'm kicking myself as I had the tool in my possession a long time ago, but no, I don't remember the name.

It's going to be pretty difficult to locate, then.  If I run across anything, I'll mention it, but the odds are small.

It was a DOS app as I recall, run from the command line, something like VGATEST.EXE.

Well, you've tried to be very helpful, so I'll just give you the points.

Ok, I appreciate it - sorry I couldn't find the solution for you.