You are basicially wanting to text a long message and hope the VZW breaks it up when sending to other carriers, right? Well, VZW does not to that for its valuable customers like all other carriers do.
I try to live within the 160 character limit, and at least on my phone, the handy little counter in the corner lets me know how I'm doing as far as message length goes. Question - you said "when sending to otros carriers" - does it send it in parts when sending VZW to VZW? Or does the 160 limit apply to ALL text messages? I know I do get texts from my sister (AT&T) that are longer and it just comes in as multiple text messages.
when vzw to vzw it is 1000 characters( that why there is a 1/7 in the upper right hand corner when composing text, meaning 1 of 7 sets of 160 characters). IF I try to send to other carrier as a text it does NOT break them up like other carriers do. Instead i get a BIG FAT FAILED message from Verizon stating that their network will not send more than 160 characters out of network. My point here is that other carriers will break up +160 character messages as a courtesy, but VZW refuses to offer that same courtesy to its valued customers.