Can an ordinary, off the shelf, computer UPS product do the same thing as an AC regenerator?
No. Computer grade UPS systems are designed to support the specific requirements of computer power supplies and while they do an excellent job of protecting from surges and provide continuous power during blackouts (power failures) they have either no or very insensitive voltage regulation, do not remove harmonic distortion, allow some noise and transient voltages through and provide less than ideal sine wave AC output.
