An ideal solution is a new service offered by CheapIntlCalls.com. They have a quad band phone that can be used throughout the world (in most countries). Their travel pack offers a mobile phone, a virtual phone number in your local area (you divert your home and mobile phones to this number), a VoIP account and up to $20 worth of VoIP credit.
When you leave home you divert your phone numbers to the virtual number provided. This then routes the call to your VoIP account. When you arrive at your new destination, pick up a prepaid sim card, put it into the SPARE sim slot (all their phones have two sim slots). Select register my phone number in the menu, and the phone will send an sms message and within 5 minutes you can be making cheap outbound calls. Go to an internet cafe, log in to your voip account, and tell the follow me system your new phone number. All of your calls to your home mobile and home number will now be routed to your new country at voip rates.
If there are no access numbers available, you can simply set the phone for callback. When you dial a number from your phone, the phone intercepts the call and places a call to the call back number for you. A minute or so later your mobile will ring. When you answer the phone, the system will automatically place the call to your original destination.
As the phones are equipped with two sim cards, you can put your original home mobile sim into the phone and still receive your SMS.
I am not sure whether this answers your question, but in this case the only thing you need to carry is your new mobile phone. you can find out more at www.cheapintlcalls.com