"Upconversion" is incompatible with the composite or s-video inputs of any standalone DVD recorder: they operate strictly on a 480i video signal (max). Even if you obtain a VCR with "upconversion," no current DVD recorder could directly accept the "upconverted" signal. So from the standpoint of your intended use, no, there is no such thing as an upconverting VHS vcr.
Practically speaking, that is. OTOH, if you enjoy tinkering, and have a flexible budget, there are workarounds that can approximate some aspects of upconversion and capture it with a DVD recorder. But you'd need a scarce, expensive D-VHS vcr with the component-output feature, and a DVD recorder with component inputs. The vcr would provide a cleaner signal thru its component outputs, and the DVD recorder would internally convert the component signal back into something recordable in DVD format. Whether the improvement would be noticeable or worth the expense depends on your tapes and personal visual preferences.
The two hurdles you'd face are the cost of a D-VHS vcr, and the fact that DVD recorders with component inputs haven't been made since 2005 (most of those were not very good recorders, either). You'd have better luck using a PC video input board instead of an ancient DVD recorder with component inputs. The only consumer VCRs that had upconversion and component outputs were some of the JVC D-VHS models, these are highly coveted by DVHS enthusiasts so not cheap second-hand. There were one or two DVD/VHS combo units that could upconvert their VHS output via HDMI, like the Panasonic DMR-EZ48v, but these are also now going for insane prices second hand ($200 minimum) and have issues of their own.
DVD recorders cannot accept HDMI input: you would need to add an HDMI>component or HDMI>composite converter. Inexpensive converters muddy the signal, good converters cost $200 and up. Some PC video boards will accept direct HDMI input: if you find one of the last JVC DVHS vcrs with HDMI output, like the HM-DH5U (or a Panasonic DMR-EZ48v that still works), you could connect it via HDMI to such a PC input.
In the end, after all the trouble and expense, you would probably end up with similar results connecting a vcr to your dvd recorder in the normal way and then playing the dvds in a dvd or bd player connected to your TV via HDMI. The TV's own internal upconverter usually works quite well with HDMI inputs of VHS dubs at 480: the improvement is noticeable vs the TV composite or s-video connections to a VCR playing the original tape.
The biggest advantage of a DVHS vcr is not the upconversion or component/HDMI connections, but the DNR/TBC circuit that cleans up the grain and color noise inherent to VHS. This TBC/DNR benefit applies to all DVHS outputs including composite and s-video, and can give dramatic improvements to many (but not all) tapes during DVD capture. TBC/DNR can also be found in several JVC and Panasonic SVHS vcrs, but they are older and more worn out than the JVC DVHS units (the old SVHS are not much cheaper either). If you are intent on getting the best quality VHS captures to your DVD recorder or PC, save your pennies for mint-condition DVHS vcr. They cost $250 - $500 on eBay depending on the model and condition, sometimes you can snag one for much less on Craig's List if you keep looking.
Edited by CitiBear - 9/3/13 at 7:17am