Well, like in so many of these things......."it depends". I'm using i1Profiler and an i1Pro2. I've profiled and studied the canned profiles of a large number and variety of papers from different providers over the past several years. I have not ever seen a profile reporting L*0 for the Black point.
ProfileMaker 5 and I1Profiler correctly map BP. I've only seen the issue with canned Epson profiles. Canon's also have issues but they report BP correctly. What canned Epson profiles have you looked at?
Incorrect BP reporting dominates what I've seen from the 2200 to 2400 and 9800 Epson canned profiles that were created by Seiko profiling software. Here's two canned profiles supplied by Epson that were created by Seiko software. One for the R800 and one from the 9800/7800 canned sets. All of my other 9800/7800 canned profiles also show BP as L=0.
Profile: "C:\WINDOWS\System32\Spool\Drivers\Color\Pro9800 7800 DWMP_PK.icm"
Descr: "Pro9800 7800 DWMP_PK" Ver: 2.4.0 Copyright: "Copyright(C) SEIKO EPSON CORP. 2005"
WP: 93.6 0.6 -0.8 BP_PI: 0.0 0.0 0.0
BP_RI: 0.0 0.0 0.0
Profile: "C:\WINDOWS\System32\Spool\Drivers\Color\SPR800 Matte Paper-HW.icm"
Descr: "SPR800 Matte Paper-HW" Ver: 2.4.0 Copyright: "Copyright(C) SEIKO EPSON CORP. 2004"
WP: 95.5 -0.8 1.1 BP_PI: 0.0 0.0 -0.0
BP_RI: 0.0 0.0 -0.0I have yet to see a canned Epson profile, manufactured by Seiko software, that didn't map BP to 0 and would be curious if you have or know of Seiko, Epson profiles that report BP correctly.
But Epson also sometimes provides non Seiko profiles and these, for the limited ones I've looked at, map normally like this for the 3880.
Profile: "C:\WINDOWS\System32\Spool\Drivers\Color\SP3880 ECM MK v1.icc"
Descr: "SP3880 ECM MK v1" Ver: 2.0.0 Copyright: "Copyright X-Rite, Inc."
WP: 96.5 -0.7 1.0 BP_PI: 20.7 0.7 1.2
BP_RI: 20.9 0.6 1.0
As for your third point on peculiar results, I haven't tinkered with X-Rite's patch sets, but I find when I generate a normal patch set using one of the numbers that Ethan Hansen recommended in a recent article, the performance of both colours and grayscale is usually very satisfactory within the luminance gamut of the printer/paper combination being tested, so I don't generally see the need to tinker with these tables.
I've found Ethan's patch sets to be quite good as well and appreciate the detailed breakdown he provided for I1Profiler's set of patch sizes. I've had very good results with them.