You would need to use some type of electrotransport delivery, but it can be done using iontophoresis.
What is iontophoresis?
Iontophoresis is a non-invasive method of propelling high concentrations of a charged substance, normally medication or bioactive agents, transdermally by repulsive electromotive force using a small electrical charge applied to an iontophoretic chamber containing a similarly charged active agent and its vehicle. -
Wikipedia
Apply it to compounds we care about please:
Effect of iontophoresis on in vitro skin permeation of an analogue of growth hormone releasing factor in the hairless guinea pig model, Kumar S, J Pharm Sci. 1992 Jul;81(7):635-9
The shortened analogue of growth hormone releasing factor (GRF) Ro 23-7861 (1) has a molecular weight of 3929 daltons [equivalent to GRF (1-29)] and is more potent than the endogenous GRF (1-44). The in vitro hairless guinea pig model and vertical and horizontal diffusion cell assemblies were used to study the effect of iontophoresis on the permeability to skin of 1. The transport of 1 across the skin was studied by monitoring the rate of its appearance in the receiver compartment with a radioimmunoassay. No permeability of 1 was observed without iontophoresis, whereas with iontophoresis, the permeability of 1 was significant.
For example, at a current density of 0.23 mA/cm2 and buffer concentration of 0.05 M, the flux of 1 was 56.8 +/- 8.21 ng/cm2.h. The flux of 1 was independent of the design of the permeation apparatus, the electrodes, the donor and receiver volumes, the type of current (constant or pulsed), and the frequency of the pulsed current. The flux of 1 increased curvilinearly with the increase in salt concentration of the buffer and linearly with the increase in current.
How does this electrotransport delivery work?
Electrotransport devices generally employ at least two electrodes. Both of these electrodes are positioned in intimate electrical contact with some portion of the skin of the body. One electrode, called the active or donor electrode, is the electrode from which the therapeutic agent is delivered into the body. The other electrode, called the counter or return electrode, serves to close the electrical circuit through the body. In conjunction with the patient's skin, the circuit is completed by connection of the electrodes to a source of electrical energy, e.g., a battery, and usually to circuitry capable of controlling the current applied by the device through the patient.
Depending upon the electrical charge of the species to be delivered transdermally, either the anode or cathode may be the active or donor electrode. Thus, if the ionic substance to be driven into the body is positively charged, the positive electrode (the anode) will be the active electrode and the negative electrode (the cathode) will serve as the counter electrode, completing the circuit. On the other hand, if the ionic substance to be delivered is negatively charged, the cathodic electrode will be the active electrode and the anodic electrode will be the counter electrode.
Alternatively, both the anode and the cathode may be used to deliver drugs of appropriate charge into the body. In this case, both electrodes are considered to be active or donor electrodes. In other words, the anodic electrode can deliver positively charged agents into the body while the cathodic electrode can deliver negatively charged agents into the body. -
European Patent EP1028706 "BUFFERED DRUG FORMULATIONS FOR TRANSDERMAL ELECTROTRANSPORT DELIVERY"
So basically the peptide would need to be charged and then you could use this method to drive it through the skin. I've always been curious about this. So ironlunch it would be cool if you would try this and report back...please....pretty please. 
