In the Jon Renau line, there are two colors that would make good substitutes to BelleTress's Mocha with Cream:
30A27S4: Shaded Peach and 24BT18S8: Shaded Mocha
Shaded Peach has more auburn than the Belle Tress shade does, but they both contain shade 30, which is a medium auburn. It also has rooting that is a shade lighter than Mocha with Cream.
You can watch Heather's in-depth color spotlight on Shaded Peach here:
Shaded Mocha has gold blonde highlights blended throughout, making this shade a bit warmer than Mocha with Cream.
You can watch Heather's color comparison on Shaded Mocha here: