Merge two fields using Display suite, like views inline fields
Here's a list of possible approaches:


Code field: You can accomplish this with a custom code field in Display suite. A code fields supports usage of tokens and html. Additionally, you can use a Display Suite code filter to use php itself. More info found here: http://www.youtube.com/watch?v=mvFP16PJt4c
Use a Custom formatter: If you need more heavy processing you can utilize the custom field formatter module.
Preprocess Field: Additionally, you can access variables that are preprocessed via a "preprocess field". A preprocess field will print out the value of the key in the $variables array. Lullabot has an example on using the preprocess field.
Entity Views Attached: This might be a bit extra overhead but if you download the eva module you can create views and pass the current NID in and combine fields through views. This is often helpful if you need to create various different photo galleries with different fields, etc.