  The number of low-mass brown dwarfs and even free floating planetary mass
objects in young nearby star-forming regions and associations is continuously
increasing, offering the possibility to study the low-mass end of the IMF in
greater detail. In this paper, we present six new candidates for (very)
low-mass objects in the Taurus star-forming region one of which was recently
discovered in parallel by Luhman et al. (2009). The underlying data we use is
part of a new database from a deep near-infrared survey at the Calar Alto
observatory. The survey is more than four magnitudes deeper than the 2MASS
survey and covers currently ~1.5 square degree. Complementary optical
photometry from SDSS were available for roughly 1.0 square degree. After
selection of the candidates using different color indices, additional
photometry from Spitzer/IRAC was included in the analysis. In greater detail we
focus on two very faint objects for which we obtained J-band spectra. Based on
comparison with reference spectra we derive a spectral type of L2+/-0.5 for one
object, making it the object with the latest spectral type in Taurus known
today. From models we find the effective temperature to be 2080+/-140 K and the
mass 5-15 Jupiter masses. For the second source the J-band spectrum does not
provide a definite proof of the young, low-mass nature of the object as the
expected steep water vapor absorption at 1.33 micron is not present in the
data. We discuss the probability that this object might be a background giant
or carbon star. If it were a young Taurus member, however, a comparison to
theoretical models suggests that it lies close to or even below the deuterium
burning limit (<13 Jupiter masses) as well. A first proper motion analysis for
both objects shows that they are good candidates for being Taurus members.
