Good model for comparative genomics in relation to temperature adaptation
As a starting point I would suggest you look at genomes of thermophiles and hyperthermophiles (organisms that thrive at upwards of 40 °C and 60 °C respectively), which are often found near underwater volcanos or hot springs.

For instance, one could do a genomic analysis of the archaean Methanocaldococcus jannaschii, comparing it to mesophilic species of Methanocaldococcus or Methanococcus. This organism is well studied, and genomic information for this organism is readily accessible.

Some studies have been done comparing the genomes of mesophiles and thermophiles. For example, Zheng and Wu (2010) found a correlation between GC content in coding/noncoding regions and temperature conditions.

At the other end of the spectrum you could examine psychrophiles (organisms that grow at low temperatures, −20 °C to +10 °C). However, few of these organisms are obligate psychrophiles, meaning many can thrive at higher temperatures as well and thus may not be suitable for your purpose.