I love my Line 6 DL4.

You can always tell a good stomp box pedal. They NEVER go on sale used.
You hardly ever see the DL4 used.

It has forwards/reverse/half speed/double speed/ a separate digital delay with modulation,
feedback and speed controls that you can add to any layer AND it has really nice digital
modellings of all the famous pre-digital delay pedals (including the tube echoplexes,
solid state echoplexes, roland tape echoes, analogue echoes, filter sweep echoes, etc.)
if you don't use it as a looper.

Only 14 seconds of loop (28 in half bandwidth/half speed) but I find this accomodates two bars
at almost any tempo. Loops longer than 28 seconds tend not to be heard as loops anyway (not that they
aren't fun to used occasionally).

I love my DL4. I have three of them (and I own all of the expensive hardware loopers on the market: the Looperlative, the Echoplex
and the Electrix Repeater) so that says a lot.

you are right, though I use several without this capability.

If so, you are referring (in hardware) to
the Looperlative
the Gibson EDP
the Electrix Repeater
(any others I'm not aware of)

Of these, only the Looperlative is currently in production though there is some chance that
Electrix may surface again at the Winter NAMM show this coming January in Anaheim.

You can find these units used occasionally but they are pricey. The Looperlative is the cadillac
hardware looper and it costs around $1,500 street price.

If not, then you are looking at spending some big bucks to buy something like Ablteon's Live or
Cycling 74 (and several others) on top of buying a good laptop and an audio interface for it.................all of which will set you
back a couple of grand at least.