I'll give you two options. Ruger Super Redhawk
http://www.ruger.com/products/superR...DE/models.html or a S&W 629
http://www.smith-wesson.com/webapp/w...layErrorView_Y. either would give you the option of .44Mag or .44 Special. Both offer at least two barrel lengths and holster manufacturers offer chest holsters for both.
http://www.diamonddcustomleather.com/Chest_Holsters.php If you want to customize either Bowen Classic Arms will fix you up for a price.
http://bowenclassicarms.com/
I hope this gives you a starting point.