Kaidomain has some cool new products for flashlight enthusiasts who want quad LEDs in the 20mm format:
Unfortunately the optics are >20mm and won’t fit the S2+, but you can put them in slightly bigger heads.
Thank you for this! Just nabbed a quad 219b 3500k p60 drop-in and some much need spacers!
These are not new (literally years old bad design) and often problematic quad boards/optics. When you assemble them be very careful about how the optic and PCB fits together. It can work it’s just not a drop in solution like you may be used to with the plethora of triple options.
XHP70x configuration depends on the MCPCB; I haven't seen a properly done 12V MCPCB in the chinese market with the exception of the above by LedDNA.
The GT-FC40 or other 4S/12V emitters can be driven with an H2-C driver (now upgraded, more powerful). One good thing I see in the H2-C driver is that it supports 2S battery input, or input from 2 cells in series. With 2S cells I am fairly sure the current output could be risen a good deal further without problems. 
Too bad H2-C is 2.2A only.
I’ve been looking for a good driver for this LED and aside from 4S FET ones the only good option that I see is GXB100 - but probably only one was ever made.
The Convoy XHP35 driver was tested to be quite “overclockable” (see Convoy XHP35 Driver Analysis / Testing / Schematic). This new H2-C is still untested, but stock it works with 2S input which is a plus concerning efficiency and power input capability (double voltage by the current is twice the input power).
Looks with great modding potential, hope they didn't cheaped out on something with it.
Quad Seoul SZ5 MCPCB, LED & Optics
Interesting price for 4x emitters, MCPCB (emitters already soldered) and optics are also included. for a quick and dirty quad build.
anybody knows more about Seoul SZ5 LEDs? are they any good?
Thanks.
edit if the link above doesn’t work (does NOT work for me), then please copy/paste this one:
Interesting news. 
Will there be other tints and is there an increase in efficiency?
6500K only? I’d like to see this LED tested by someone before buying.
The crappiest versions usually come first. For n00bs with crappy low CRI cool white flashlights to wander at night… :-D
I hope the 5D(4) bin will become available once.
Datasheet goes down to 5000K, but that's it, but still U4: https://www.cree.com/led-components/media/documents/data-sheet-XM-L3.pdf
also spec'd at 5 amps max. The XM-L2's were spec'd at 3 amps max. There's some hope here.
I ordered 2, but no promises about when the test will be done.
Nice, thanks djozz! Put 2 in the cart but need something more to order...
How long is too long to wait in the current climate? I’ve been waiting 3 months now. The only info I have from tracking is from 3 months ago “Information Received – Item En Route to Postal Facility”. I’ve received a number of different orders since and fear the worst 
I literally had an AliExpress order take 90 days to reach me, from March to June. I could still see it shuttling between shipping facilities, though – presumably while the shippers were looking for a route that was still open – until the tracking number expired on day 79. The fact that you’re not getting any updates would make me a bit nervous.
I track my orders on Numbers (on Mac) to gauge what order is where.
the average shipping speed across ebay (CN vendor), AliExpress, and Banggood is about 17 days from payment to mailbox. But there are also a few really delayed shipments that are beyond 45 days now
One shipment came in after 61 days (tracking stopped worked the week before delivery), one item is “in transit” for almost 48 days now with no updates at all.
I would say the system still works, but with mixed results. Guess it is exactly as pre-pandemic
I paid $18 for DHL shipping after reading the comments above; received a C21 XHP70.2 7 days after ordering.