Juan Gon is a little tempting, but I'm scared by all his injuries. You really can only expect him to play half the year. Here's the age, games played last year, and EQA (.260 is average) last year for some candidates:

JuanGon 34 82 .291
Sanders 36 130 .298 (higher than past years)
Jordan 37 66 .284
Guillen 28 136 .304 (fluke)
Mondesi 33 143 .280

Long 28 140 .237
Cedeno 29 148 .249

Just to provide an example of what these guys are worth, Sanders was worth about 3 wins more than Cedeno offensively last year.
But as bad as Cedeno has been, his EQA has been better than Long each of the last 3 years.

In conclusion, Guillen seems very unpredictable and most of the rest of the guys are risky because of their age and injury history. I think Sanders would be my first choice if we could get him to agree to a one-year deal, otherwise, maybe Mondesi. If Juan Gon was willing to do a one-year deal (which might be in his best interest anyway), it would obviously be tempting to try to catch lightning in a bottle.