I think too many of us are getting hung up on softproofing. If you've got a decent pro printer and professional quality monitor, both properly calibrated, the results should be very close. Your own experience of any minor quirks of reproduction should be sufficient to make any adjustments prior to output. Softproofing is by its very nature only a simulation.
We are using the 3800 with Epson Premium Semigloss and Fuji-Hunt Satin. With regard to what is seen on the monitor, and the colour accuracy and tone reproduction of the prints from the machine, the results are as close as you could wish. When we softproof it's really to see what difference perceptual or relative saturation makes.
I do concede though that there is possibly more of a case for softproofing if printing to matt papers if only because when viewing the image in Lightroom (or Photoshop without 'Proof Set Up' ticked), the shock of a flat, desaturated chalky image as it appears on the print can be very disheartening.
I agree that once you know what you want and what the translation is from screen to print (along with good profiles and CM workflows, SP is not such a helpful tool. While I admit to using it to view rendering options, I rarely work from a copy and make destructive adjustment layers to fix what I see can be better. I take that view, understand what I need to do in the develop module and apply the rendering I decided was best.
I find there are 3 big problems.
1] I've been told in a forum that if one uses color management properly, that the print and screen should look identical. (my attempts to correct this notion provided only ugly denials) I trust this forum's participants understand the differences between a transmissive screen image and a reflected print.
2] Almost everyone on this forum seems to know how to calibrate a monitor, but there is a huge difference between a calibrated monitor and one that you can correctly balance a print, especially LCDs. I still have my old expensive large CRT, but added a 20" widescreen LCD about a year age. I love the qualities of the LCD for almost everything. I only turn my CRT on now when I'm correcting imagery. It is many times better for print matching--the LCD doesn't come close or really work at all. The Macs at school have 20" Cinema displays (inherited) and they are better, good enough to teach color correction in PS (via ACR) about 75 students a year, but I had to make them noticeably darker than did the calibrator (I know that's a no no) to get them close. When a print isn't right yet correctly made, I have more difficulty than at home (CRT) to correct things. The big problem is that you can calibrate a cheap or midrange LCD and it still sucks or you can use a calibrated Eizo CG display and get an excellent translation. I have been looking at Eizo CG, & CE monitors, and LaCie and the new NEC top of the line like the one the gray guys (Michael & Jeff) use on the new ACR tutorial. I think those are the only current LCD displays that are anywhere as good for color correction as the best CRTs
3] Soft proofing, in my opinion, is not for beginners even though they may need it the most. I really think you need to have a lot of color sensitivity with your vision as well as how to change what you see. My idea is to try to teach the basic conversion differences and printer needs and let the expense of bad prints do the teaching. It is not that difficult and is very similar to the problems I had making photographic prints from transparencies (via internegs) for picky photographers. They would look at their 35mm Kodachrome with a 4x Schneider glass loupe and tell me my 20x24 print didn't look like the chrome! The problem was worse then since the control without making separations was very limited. At least with digital prints, we can change the HSL of eight colors and individually correct the density and contrast all along the curve.