Modern wireless networks  use  QAM  modulation with mappings that are derived from square signal constellations in which the number of signal points is an even power of two. In the particular case of IEEE 802.11 networks, these mappings are 4-QAM, 16-QAM and 64-QAM and are hereto referred as even- power QAM mappings. This paper considers the performance improvements that are obtained by adding odd-power QAM mappings (obtained from cross QAM constellations) to the set of available mappings. These odd-power mappings are associated with 22m-1-QAM  cross  constellations  that  are  carved  out  from larger 22m-QAM square constellations. For the specific cases of 8- QAM, 32-QAM and 128-QAM mappings, the improvements in throughput are quantified assuming a Rayleigh fading condition. Furthermore, in order to illustrate the use of bit metrics generated by a demapper, also examined is the performance of bit-interleaved 8-QAM and 32-QAM mappings with binary codes over an AWGN channel.