Can a constant-current stepper driver be coerced to act like a constant-voltage driver?
Unless there is some nuance of the question I am missing: 

A constant voltage (L/R type) stepper motor driver for a stepper motor is a pair of H-bridges, with no current limiting / chopping. It is not that these devices are no longer made, they are typically not sold as "stepper motor drivers". 

For instance, the classic L298 (L298N, L298D) dual H-bridge IC will drive a bipolar stepper in constant voltage mode, thus:







simulate this circuit &ndash; Schematic created using CircuitLab

Eliminate the sense resistors, and there is no current limiting left - or preferably leave them there, and size them purely for failure conditions i.e. short circuit protection.

At 160 Ohms minimum coil resistance and a 35 Volt motor supply, the resultant maximum 219 mA per channel is easily handled by the L298's 2 Ampere per channel DC current rating. 

The L298 in its various variants is still manufactured: Go with the L298D to take advantage of the integrated back-EMF protection diodes, given the inductive load.

While there are also MOSFET based H-bridge ICs available, offering greater efficiency, this may be irrelevant in a design where the efficiency loss in the series R added to each coil is likely to be the biggest heat contributor anyway.



About using a chopper driver as an L/R driver: The qualified answer is yes, as long as basic full-step driving is being attempted. It is only with micro-stepping that fine current control becomes a necessity.

Some chopper drivers may not like not receiving current feedback, and may flag a fault, but the typical full-step driver will not care, it will simply pass all current up to the resistance-limited value of the stepper (160 to 219 mA per channel, at given coil specifications), and not initiate chopping.