Have a look at one of these it has a 5" screen very readable in sunlight running pocket fms and memory map and excellent battery life
http://cgi.ebay.co.uk/XDA-FLINT-Smartphone_W0QQitemZ320382459044QQcmdZViewItemQQptZUK_Mobile Phones_MobilePhones?hash=item4a98485ca4&_trksid=p3286.c0.m14 &_trkparms=65%3A12|66%3A2|39%3A1|72%3A1683|240%3A1318|301%3A 1|293%3A1|294%3A50