The idea starts with the fact that characters have to wear all their items on their person. As well as a weight all items are given a length, breath and volume value. You would then be able to carry a sack, in which you could put items that fit, using the length and breath values and as many items as the volume of the sack allows. Items could also be carried on your person. Such as strapped to your back if you don’t have a sack their or on your belt, etc. The length and breath would take the minimum possible, for example a tefusang skin could be rolled to take up less space.
Now the main part of the idea is that 'pat down' command would be part of the pick pocketing skill. This would allow the player if they get close enough to know what sort of items the other character has in their sack or any other item in which other items are concealed. How much pick pocketing skill you have determines how accurate that is for example at the lower levels you may see "there is a sharp object in 'playernames' sack" and at higher levels it maybe "there is a dagger in 'playernames' sack", as well as this the bigger the volume of the item in the sack the more likely it is to be felt. Also depending on skill would be whether or not you get caught doing this, if you do the other player is alerted. With the 'ol big red letters if you really screw up or just a message in the chat window if it is more subtle. Assuming you weren’t caught an inventory window comes up with all the items you felt, be it just 'round object' and gives an approximate size or 'apple' and an exact size depending on your skill you then get to pick one thing to try and steal. The success of this is them decided by how secure the sack is, the other persons pick pocketing skill, the weight and the volume of the item, 'cos if someone tries to steal the coat off your back you more likely to notice than if they pinch an apple from your pocket. From there you can either fail to get the item and be spotted, fail to get the item and get away with it but trying again on the same person would mean a more likely chance of being caught, getting the item and being spotted, getting the item and getting away scot free. Other people in the area with a higher pick pocketing skill than you may still notice if the person you where pick pocketing didn't, so getting away with the booty with no one noticing would be rare. Now in any case, if you have succeeded or not, if the player you where pick pocketing notices and challenge you auto accept. This means that another person nearby could alert the victim to your attempt and they would then know to challenge you even if they hadn't noticed in the first place. If they do notice in the first place they auto target you and are prompted whether to dual you or not. At this point you scarper. For the next 2 minutes the AI guards will attack and arrest you on sight IF the pick pocketed player uses a command along the lines of /alert 'yourname'. The option of alerting would also pop up if they decline to dual you. Items could be stolen from any part of a person but obviously stealing something off their back would be much easier than stealing something right out their hands.