Info: Cheap places to crash for the night in Japan

Yikes! You've been out partying in Tokyo and missed the last train for the night. You need to crash, but where? Here's my list of cheap  ways to spend the night in Tokyo:

1. Net cafe:  Many manga+net cafes are 24 hours and have private cubicles that you can crash in. They have "overnight" rates which are quite reasonable, coffee and soda machines, and of course manga comics and networked PCs. Some even have massage machines, tanning beds and foot spas! The "night pack" price for a random netcafe that I googled in Shinjuku is a measly Y1500...
2. Super Sento Bathhouse: Many of the larger "super sento"-type bathhouses have relaxation rooms where you can spend the night. It might cost an additional Y1500 on top of the Y1000 admission fee, but still Y2500 for the night (and all the hot spa baths you can handle) isn't too bad.
3. There is of course the capsule hotels. I'm claustrophobic so this isn't an option for me.
4. Business hotels:  the cheapest business hotels like Super Hotel or Toyoko Inn have rates that start around Y4980 for a single for the night. The problem is that these cheapo hotels don't tend to be in front of popular train stations, so getting to one might be an issue. And the rooms tend to fill up quickly.

I was inspired to write this because of two random events that happened this summer:   one of my students almost got stuck herself stuck by herself in Osaka overnight .... and I went to the Oedo Onsen Monogatari bathhouse yesterday with my sweetie and noted that they had a very nice women's only "relaxation room" with full reclining chairs and individual TV sets -- and there appeared to be several patrons who were gearing up to spend the night there.

Oedo Onsen is quite expensive, Y2000 for general admission and another Y1700 for spending the night (in their lingo "extra late-night fee"), but other super sento in Japan are cheaper.